## land will mourn, and the heavens above will darken ##

Jeremiah emphasizes Yahweh's judgment by saying that the earth itself expresses great sorrow.  (See:[[rc://en/ta/man/translate/figs-personification]])

## cavalry ##

a group of soldiers riding horses

## every city will flee... every city will climb ##

This emphasizes that all of the people will be running away.

## The cities will be abandoned, for there will be no one to inhabit them ##

These two clauses have similar meanings. The second one strengthens the thought in the first. (See” Parallelism) AT: "There will be no one left in the cities."